This document discusses rate-controlled drug delivery systems. It defines rate-controlled systems as those that release drugs at a predictable and reproducible kinetic rate. The document classifies these systems into four types: 1) rate-preprogrammed systems that release drugs at a set rate, 2) activation-modulated systems whose rate is altered by an activation mechanism, 3) feedback-regulated systems whose rate is controlled via feedback, and 4) site-targeting systems that deliver drugs to specific sites in the body. Examples of rate-preprogrammed systems are provided, including polymer membrane and matrix diffusion-controlled systems.

1. Rate Controlled Drug Delivery System
■ Presented By : Vilas Pawar
■ First year M pharmacy
■ Department of pharmaceutics
■ Under the guidance of : Prof. A. H. Hosamani
■ Government College Of Pharmacy, Karad

2. Contents :
■ Introduction
■ Definition
■ Principle
■ Fundamentals
■ classification

3. Defination:
The term “controlled release,” on the other hand, has a
meaning that goes beyond the scope of sustained drug action.
It also implies a predictability and repre ducibility in the drug
release kinetics, which means that the release of drug
intregrated from a controlled release drug delivery system
■ Drug ingredient(s) from a controlled-release drug delivery
system proceeds at a rate profile that is not only
predictable kinetically, but also reproducible from one unit
to another.

4. CLASSIFICATION OF RATE-CONTROLLED
DRUG DELIVERY SYSTEMS :
Based on their technical sophistication controlled-release drug
delivery systems that have recently been marketed or are under
active development can be classified as,
1. Rate-preprogrammed drug delivery systems.
2. Activation-modulated drug delivery systems .
3. Feedback-regulated drug delivery systems .
4. Site-targeting drug delivery systems.

6. A. Polymer Membrane Permeation-Controlled Drug Delivery System
In this type of preprogrammed drug delivery systems, a drug formulation is totally or
partially encapsulated within a drug reservoir compartment. Its drug release sur face is
covered by a rate-controlling polymeric membrane having a specific per meability. The drug
reservoir may exist in solid, suspension, or solution form.

7. ■ Polymeric membrane can be fabricated from a nonporous
(homogeneous or hetero geneous) polymeric material or a microporous
(or semipermeable) membrane. The encapsulation of drug formulation
inside the reservoir compartment is accomplished by injection molding,
spray coating, capsulation, microencapsulation, or other tech niques.
Different shapes and sizes of drug delivery systems can be fabricated

9. ■ The release of drug molecules from this type of rate-
controlled drug delivery systems is controlled at a
preprogrammed rate by controlling the partition coefficient
and diffusivity of the drug molecule and the thickness of the
rate-controlling mem brane. Representatives of this type of
drug delivery system are as follows:
1)progestasert IUD,
2)Norplant subdermal implant,
3)ocusert system
4)Transderm -Nitro

10. • B. Polymer Matrix Diffusion-Controlled
Drug Delivery Systems
• In this type of preprogrammed drug delivery system the drug
reservoir is prepared by homogeneously dispersing drug
particles in a rate-controlling polymer matrix fab ricated from
either a lipophilic or a hydrophilic polymer.
1)Nitro –Dur
2)The compudose subdermal implant

11. C. Microreservoir Partition-Controlled
Drug Delivery Systems
In this type of preprogrammed drug delivery systems the drug reservoir is
fabricated by microdispersion of an aqueous suspension of drug using a
high-energy dispersion
technique (22-24) in a biocompatible polymer, such as silicone
elastomers, to forma homogeneous dispersion of many discrete,
unleachable, microscopic drug reser voirs. Different shapes and
sizes of drug delivery devices can be fabricated from this
microreservoir drug delivery system by molding or extrusion.

12. ■ Technique (22-24) in a biocompatible polymer, such as silicone
elastomers, to form
■ a homogeneous dispersion of many discrete, unleachable,
microscopic drug reser voirs. Different shapes and sizes of drug
delivery devices can be fabricated from this microreservoir drug
delivery system by molding or extrusion.

21. ■Thank you